Solve for $x$ and $y$ using substitution. ${2x-4y = -8}$ ${x = -y-7}$
Explanation: Since $x$ has already been solved for, substitute $-y-7$ for $x$ in the first equation. ${2}{(-y-7)}{- 4y = -8}$ Simplify and solve for $y$ $-2y-14 - 4y = -8$ $-6y-14 = -8$ $-6y-14{+14} = -8{+14}$ $-6y = 6$ $\dfrac{-6y}{{-6}} = \dfrac{6}{{-6}}$ ${y = -1}$ Now that you know ${y = -1}$ , plug it back into $\thinspace {x = -y-7}\thinspace$ to find $x$ ${x = -}{(-1)}{ - 7}$ $x = 1 - 7$ ${x = -6}$ You can also plug ${y = -1}$ into $\thinspace {2x-4y = -8}\thinspace$ and get the same answer for $x$ : ${2x - 4}{(-1)}{= -8}$ ${x = -6}$